1. Field of the Invention
This invention relates to a contactless ignition device, and more particularly to a contactless ignition device of excellent waterproof property which is suitable for use in automobiles etc.
2. Description of the Prior Art
Heretofore, contactless ignition devices have been such that an induced voltage is obtained from a signal generator for generating a signal synchronous with the engine revolution, that the voltage is processed by electronic circuitry, and that a high voltage is produced in an ignition coil according to the number of revolutions. In some of such contactless ignition devices, the electronic circuitry is mounted directly on the proper of a distributor so as to reduce the numbers of man-hours in assemblage and in interconnections. The electrical couplings between the electronic circuitry and other equipments are made by the use of connectors. However, when a waterdrop or the like adheres between the terminals of the connectors, especially between the connector terminals across which an output from the signal generator is applied, a distortion in the signal waveform or a lowering in the output voltage arises due to leakage, with the result that the ignition point deviates from the optimum value or that energy to be supplied from the ignition coil to an ignition plug becomes insufficient. In the prior-art ignition devices, therefore, the amplifier circuit and the signal generator are coupled by lead wires.
Such techniques are disclosed in Japanese Utility Model Application Publication No. 49-33615 and Application Publication No. 49-33623.
Further, Japanese Utility Model Application Publication No. 46-17535 and Japanese Patent Application Laying-open No. 52-22639 teach expedients in which the amplifier circuit is mounted on a side surface of a housing of the distributor. With such methods, however, the connection between a pickup coil and a circuit unit is troublesome. When the circuit unit has lead wires, the fabrication is inconvenient. On the other hand, when it is connected by the use of connectors, malfunctions occur due to a waterdrop.